Alkenylaminoacetonitriles



i The new alkenylamifioacetonitriles-may bepr e pared by several 'methoda'The preferred metho involves several s'tepsrthef'first of wlifch is to pr pai s the. corf'espondingt 'aikenyialniinomethaii 'f' reactions may be ""'equations, in which'fl is an alkenyl radical ha Patented Aug. 23, 1949 inid Company, New fa l'icazQ-f Marines 1 rt I 1 This invention relates to new alkenylamin acetonitriles Th om ound than five carbon atoms, the term alkenyl bein aaa to d iiotdan rhdriovaient 'aliphaitic hydrocarbon radical containing a double bond. Ex-

The compounds are useful fofitliemrparatiti of the,corresppnding alkenylglycines, and are sulfonic aciq salt T i followed by r t with a'metar'eyamu ing not more than five carbon atoms.

RNH1 HCHO +NaHSOa OH:

SOzNa ON In the first step it is preferable to use substantially stoichiometrical quantities of the alkenylamine and alkali metal formaldehyde bisulfite solution. This gives the best results and is preferred. The formaldehyde alkali metal bisulfite solution is suitably prepared, for example, by dissolving sodium meta disulfite in water to give approximately a 40% solution, cooling to 20 C. or lower, and adding an equivalent amount of commercial 37% formaldehyde solution. The formaldehye bisulfite solution is then added to an equivalent amount of the aqueous alkenylamine solution, preferably using external cooling to maintain the temperature at about 20 C. A slightly better yield results when the formaldehyde bisulfite is added to the amine, rather than in the reverse order.

The alkali metal salt of the alkenylaminomethane sulfonic acid can be isolated, if desired, by evaporating the aqueous solution to dryness, preferably under reduced pressure. The neutral compound can be obtained from the alkali metal salt by dissolving in a minimum amount of water, clarifying the resulting solution, if necessary, and

seas 202 necessaryizimritirmanni, :1:

r-fDhis anay takeecplaoa' ah mosa emm NHR itaris desired: taispeedaunathereaetio NaCN mm. taheatingbiior zexampleeumtolalight 70 C. may be 1 30 used without seriously lowering the yield.

Serial No. 63%406 hyde 'and then passiiagtiiiisulfurdioxide amtil precipitatime'occursabutetiiise reactiomisgdiflicult to carry out in larger scaleoperatians andethe yield is 10w? aerate: a teii'dendy iomanytexcess sulfur i'oxide p re'aeii' witlrsthe talkenmsgroup at the to give compliostingtisideireactions. The so'lutiori 'of the alkali. of the alkenylaminomethaneg: sulfonic acid, prepared as described aboveandcon taining no excess bisul- 1 "fite, is'addedtp an equivalent quantity of technical? grader emetalrcyanide solution. he ?onderaofladditiomihereris. unimportant, the aid berngdapproximatelyi an either he temperaturaiisapmi ffibty Wi below lthough asiimthe finststepathe'aemper ture is mot, cniticahatilehiseisanradlantage of the rocess as delicate temperatur controls are not 55E! rAf-te-rrthe additionofhe me a cyan de is comretest-he mixtuneimayziue;stirredaoreatnum r of oursmntiietherreaetiom has meats; complet on. re or, if moderate In order to obtain maximum yields of the alkenylaminoacetonitrile the dilution of the reaction mixture requires some attention. The best concentration will vary a little with the particular nitrile, but in general should be at least 13% of the total reaction mixture (assuming quantitative conversion of the nitrile). Substantially decreased concentrations result in the lowering of yield. On the other hand, higher concentrations may be used but the improvement in yield is very slight and if the concentration becomes too high certain operating difficulties arise.

When the optimum volume of water has been used for the reaction, the alkenylaminoacetonitrile will separate from the reaction mixture as an upper layer which is an aqueous mixture of the nitrile containing also some sodium sulfite. To remove this water, a suitable solvent, for example chlorobenzene, is added to the reaction mixture. In this way, a nearly anhydrous solution of the nitrile in the solvent is obtained. If too little water has been used during the reaction, it may be necessary to dilute the mixture after reaction is complete to avoid emulsion formation during the extraction of the nitrile. The use of a solvent serves the additional advantage of extracting from the aqueous solution a small amount of the nitrile which remains dissolved in it. The nitrile is obtained by distilling off the solvent.

For practical purposes sodium formaldehyde bisulfiteand sofdium cyanide are preferred because of their cheapness. However, the particular metal is not important and any water solubl metallic salt may be used. For example, when potassium cyanide is used in place of sodium cyanide in the second step the yields are slightly" higher, but not sufficiently so to justifyrthe added cost. metal salts give satisfactory resultsand, may be used wherever the economies of. the operation permit.

It is an advantage of theprocess of our invention that the nitrile is obtained in a form su'fiici ently pure that it is unnecessary to isolate and further purify the nitrile for further reaction. For example, in case it is to be used for the preparation of the corresponding'alkenylglycine,

hydrolysis may be brought about by slowly adding the solution of the nitrile in the solvent to an equivalent quantity of dilute caustic alkali solution, heated to 90-95 C; Afterseparating the :solvent and'di-stilling to remove the ammonia,

Other perature for a number of hours during which time the desired nitrile separates along with some water as the upper layer. It is isolated in excellent yield by extraction with 81.1 Parts of chlorobenzene and distillation of the chlorobenzene solution. Allylaminoacetonitrile is a colorless liquid distillingat 60 C, under a vacuum of 5 of Inercury.

EXAMPLE 2 Preparation of methallylaminoacetonitrile When the procedure of Example 1 is followed with the substitution of 74 parts of 96% methallylaminel for the allylamine, methallylaminm alkenylglycine of suflicient purityis obtained in I aqueous. solution.

- The invention will be more fully set forth in connection with the following specific examples,

= which are illustrative only and not by way of limitation. All parts are by weight.

EXAMPLE 1 I Preparation of allylaminoacetonitrile A-solution of. 101 parts of technical sodium -meta-bisulfite in 228 parts of water is cooled below 20 and treated with 81.1 parts of commercial 37% formaldehyde. The resulting solution of thefsodium 'bisulfite-formaldehyde addition compound is then added slowly to a cooled solution of 5'7 partsof allylamine in 75 parts of water. The reaction is immediate and exothermic and Y it'is'" advisable to use external cooling to hold the temperature below about 20 C. To the resulting solution of sodium allylaminomethane sulfonate added a solution of 51.2 parts of technical sodium cyanide in 150 parts of water. The reaction mixture is then stirred at room tem- REFERENCE S CITED The following references are of record in the file of thispatent:

UNrrE STATES PATENTS Number Name Date 2,228,271 Jacobson et al. Jan. 14, 1941 2,328,940 Alderson et a1. Sept. 7, 1943 2,375,016 Marple et al. May 1, 1945 FOREIGN PATENTS Number Country Date 460,372 Great Britain Jan. 26, 1937 792,962 France Nov. 7, 1935 

